Anemometer for Arduino

This is an Anemometer for Arduino. The bottom and the top part come together with an ball-bearing. In the bottom part is a reed contact and a magnet is in the top part. With an Arduino you can measure the time between two peaks from the reed contact. With this information you can measure the wind speed.

You can watch the assembled anemometer here: https://www.youtube.com/watch?v=VI9HWjiexwA